Air circulation



Ju ly 27,jl937. M. WEBER 2,088,312

AIR CIRCULATION I v Filed Aug. 28, 1933 3 Sheets-Sheet 1 Patented July27, 1937 UNITED STATES PATENT OFFICE 3 Claims.

The present invention pertains to the circulation of air in a. room orother inclosure and its object is to provide an improved, novel andhighly eflicient method of air circulation whereby substantially all ofthe air in the room in which the method is carried out or practiced iscaused to rotate helically about a central, horizontal axis in order tomix together the nitrogen, oxygen, carbon dioxide and other contents ofthe air and thus obtain uniformity of the air throughout all portions ofthe room or inclosure. In general, this method consists in directingacross the room and above head height a central stream of high velocity,helically moving air and discharging a plurality of high velocity airstreams in such manner and form that they flow helically around thecentral stream of helically moving .air and cause all the surroundingair in the room or inclosure to revolve and move in harmony therewith.

The invention consists in the method which is hereinafter described indetail and set forth in the accompanying claims.

In the drawings which accompany and form a part of the presentspecification or disclosure and in which like numerals of referencedenote corresponding parts throughout the several views:

Figure 1 is a view, partly in side elevation and partly in section, of afan apparatus for producing the air streams of the improved method;

Figure 2 is a fragmentary perspective showing by arrows the manner inwhich the air streams emanating from the fan apparatus operate helicallyto revolve the surrounding air in the room in which the apparatus islocated;

Figure 3 is a front view of one of the blades of the wheel of the fanapparatus; and

Figures 4, 5, 6, 7, 8 and 9 are sections taken re spectively on thelines 4-4, 5-5, 6-6, 1-1, 8-8 and 9-9 of Figure 4.

The apparatus shown in the drawings represents one means or structurefor carrying out the method which forms the subject matter of theinvention. This. apparatus is in the form of a unit which is suspendedfrom the ceiling of the room or inclosure in which the method is to bepracticed. As shown in Figures 1 and 2 of the drawings. the apparatuscomprises a fan wheel I0 and is spaced from one of the end walls of theroom a distance substantially equal to one-fourth the length of theroom. The fan wheel I0 is in the form of a one-piece casting andcomprises an elongated, sleeve-like huh II and five radially extendingblades l2. The rear end of the hub II is journalled in a bearing l3 on aplatform ll so that the fan wheel is rotatable on a horizontal axis. Theplatform It is suspended from the ceiling of the room by straps i5 andthe bearing I3 is positioned on the platform so that the fan wheel iscarried above head height and is spaced substantially equidistantly fromthe side walls 5 of the room. In practice it has been found that themethod may best be practiced by positioning the fan wheel at anelevation of approximately eight feet from the floor of the room inwhich the air is to be circulated.

In addition to the wheel Hi, the apparatus comprises a centrifugalblower l6. This blower, as shown in Figure 1, is located on a platformI1 and is driven by an electric motor It. The

platform I! is suspended from the ceiling of the 10 room by the strapsl5 and is positioned above the platform l4 and in close proximity to theceiling. The electric motor I8 is mounted on the platform H in front ofthe blower l6 and has the rear end of the armature shaft thereofconnected to the 20 blowers rotor (not shown). The blower embodies acentral inlet (also not shown) in one of the side walls of the casingthereof and has a conduit l9 connected to the casing outlet. Thisconduit extends downwardly from the blower l6 and is provided at thelower end thereof with a fixed or non-rotatable discharge tube 20. Thelatter ex-. tends longitudinally through the central portion of the hubH of the fan wheel Ill and is arranged so that the air compressed by theblower and delivered to the conduit I9 is discharged forwardly from thecenter of the fan wheel in the form of 'a stream which is shown bydotted lines in Figures 1 and 2 of the drawings and is substantially ofuniform thickness from one end thereof to the other. A helical rib 2| isformed on the inner periphery of the discharge tube. 20 and operates tocause the air stream emanating from the tube to flow spirally as shownby dotted lines in Figures 1 and2. During drive of the blower l6 4 bythe electric motor l8, air is drawn into the blower casing by the rotorof the blower casing into the conduit l9. From the conduit I9, thecompressed air flows to the tube 20 from whence it is discharged in theform of a central stream which flows spirally in a forward directionfrom the center of the fan wheel Ill. The blower is preferably driven atsuch a speed and so constructed that the stream of air emanating fromthe tube 20 flows without substantial diminution in velocity to the farend of the room. The tube 20 is of 'such length that the central airstream is practically of the same thickness throughout its entirelength. a

The fan wheel I0 is driven by the electric u motor l8 through the mediumof anlendless belt 22. This belt extends around a pulley 23 on the frontend of the armature shaft of the motor and a pulley 24 on the hub ll ofthe fan wheel. The blades [2 of the fan wheel embody pressure faces 25at the front thereof and suction faces 26 at the back and are angledwith respect to the plane of rotation of the fan wheel so that thesuction faces operate to draw forwardly the air in back of the fan wheelinto contact with the pressure faces 25 which efi'ect air propulsion infront of the wheel. The pressure faces are in the form of longitudinallyor helically twisted, fiat surfaces and at the root or inner ends of theblades extend rearwardly at an angle of 42 with respect to the plane ofrotation of the wheel as shown in Figure 4. At one-sixth of the distancefrom the inner ends of the blades to the outer ends, the pressure faces25 are inclined or angled at 40 with respect to the plane of rotation ofthe wheel as shown in Figure 5. At one-third of the distance from theinner ends of the blades to the outer ends, the pressure faces areinclined or angled at 37V with respect to the plane of rotation as shownin Figure 6. Halfway between the inner and outer ends of the blades, thepressure faces extend rearwardly at an angle of 35 with I respect to theplane of rotation of the wheel as shown in Figure '7. At two-thirds ofthe way from the inner ends of the blades to the outer ends, thepressure faces; extend rearwardly at an angle of 32% with respect to theplane of rotation as shown in Figure 8. At five-sixths of the way fromthe inner ends of the blades to the outer ends, the pressure facesextend rearwardly at an angle of 30 with respect to the plane ofrotation as shown in Figure 9. By reason of the fact that the pressurefaces of the blades are in the form of helically twisted, fiat surfacesand decrease in pitch at the rate of 2% every sixth of the distance fromthe inner ends of the blades to the outer ends, each blade duringrotation of the fan wheel, produces a stream of air which fiows spirallyaround the central stream emanating from the tube 20. Inasmuch as thereare five blades on the wheel I, five air streams are projected by thefan wheel around the central air stream. These five streams as they flowfrom the fan wheel l0 to the fan end wall of the room in which theapparatus is disposed, producea cyclonic effect within the room wherebythe surrounding air is revolved in harmony therewith as shown by arrowsin Figure 2. For ventilating a room of large size,- such as one fiftyfeet long and thirty feet wide, a twenty inch, five bladed fan wheel ispreferably employed. At a preferred speed of 1800 revolutions perminute, the five air streams produced by the bladesof the wheel flow atan average velocity of 2770 feet per minute and 5550 cubic feet of airper minute are displaced. Because of the specific construction andformation of the blades, the five air streams travel the full length ofthe room without merging into the surrounding air, and maintainthroughout their course of movement their helical or spiral flow aroundthe centralair stream. The leading edges of the blades I2 aresubstantially straight, as shown in Figure 3, and the outer or tip endsof the blades are rounded and are substantially semicircular inconformation. The central portions of the blades are slightly less thanone-half the. length of the blades and the trailing edges are convex.The suction faces 26 are convex, as indicated in Figures 4, 5, 6, 7, 8and 9 of the drawings, and the blades are of maximum thickness near theleading edges thereof. The suction faces of the blades are sharplycurved adjacent the leading edges and the portions thereof adjacent thetrailing edges of the blades are more gradually curved. The shape orconformation of the suction faces of the blades is such that duringrotation of the fan wheel all of the air in back of the fan wheel, thatis, adjacent the near end of the room, is drawn forwardly atcomparatively low velocity into contact with the pressure faces 25.Because of the specific shape and curvature of the pressure faces of theblades, the five air streams produced by the blades during rotation ofthe wheel l0 by the electric motor l8 pulsate as they flow helicallyaround the central air stream. The pulsations of the five helical airstreams serve to set in motion the surrounding air in the room andthuscause the latter to fiow around the room in harmony with the airstreams. The pulsations are attributable to the fact that the air in thefive helical streams is compressed without restriction and hence atintervals along the course of fiow of the streams portions of the airflow outwardly. The outwardly and rearwardly extending curled lines inFigures 1 and 2 of the drawings are intended to represent the pulsationsor fluctuations in pressure. In practice it has been found that with theaforesaid twenty inch, five bladed fan. wheel there are twelvepulsations per minute when the wheel is rotated at 1800 revolutions perminute and that these pulsations occur at approximately every six feetalong the courseof travel of the air streams. As the five air streamscreated by the pressure faces of the blades leave the fan wheel, thepressure of the air in the streams builds up in increasing amount untilat approximately six feet from the wheel a portion of the air leaves thestreams and flows outwardly and helically in a rearward direction asshown in the drawings. The air remaining in the streams continuesforwardly and, as the pressure again builds, a portion of the air flowsoutwardly and causes another pulsation. This action of the air in thestreams continues throughout the entire course of the air streams. Theair which leaves the air streams and forms the pulsating eflect flowshelicallyand rearwardly and, as previously pointed out, sets in motionthe surrounding air, thus causing the latter to move around the room inharmony with the high velocity air streams air flows through the tubeand is discharged horizontally across the room in stream form. As thecompressed air flows through the tube it is subjected to the action ofthe helical rib 2| on theinner periphery of the tube and is caused tofiow helically. As previously pointed out, the

.central air stream emanating from the tube, be-

cause of the velocity of the air and shape and construction of the tube,fiows from the fan wheel III to the far end wall of the room withoutsubstantial change in form. During rotation of the fan wheel III by theelectric motor "I, the air in back of the fan wheel is drawn uniformlyand at low velocity forwardly into contact with the pressure faces ofthe blades by the suction faces 26 and is projected in the form of fivestreams which flow helically around the central air stream emanatingfrom the tube 20. These five air streams pulsate or flow in gusher formand 5 produce a cyclonic movement of the surrounding air in the roomwhereby all of the various ingredients of the air, such as the nitrogen,oxygen and carbon dioxide, are thoroughly mixed. The

pulsating or gusher character of the five helical 10 air streamsemanating from the blades sets the surrounding air in motion and causesthe air to flow in harmony with the streams. The central air streamgives force and impetus vto the five, blade-produced air streams andcauses them 15 to flow without substantial diminution in velocity to thewall at the far end of the room. The air streams, as' they impingeagainst the wall at the far end of the room, are deflected inalldirections. Byreason of the fact that the fan 20 wheel l and tube 20 arelocated at approximately an elevation of eight feet from. the floor, theoccupants of the room are not subjected to direct draft. g

The herein described method of air circulation 25 may be carried out bya fanwheel such as that shown and described in Letters Patent of theUnited States'No. 1,933,948 granted to me November' '7, 1933 or byapparatus other than that herein disclosed and contemplates delivering a30 central, helically moving stream of air across a room or inclosureabove head height and directing a plurality of high velocity airstreams,

- around the central stream in a pulsating manner so as to produce acyclonic eflfect within the room whereby the surrounding air is causedto rotate in harmony therewith and the various constituentsor componentparts of the air are thoroughly mixed together.

Having thus'described the invention, what I claim as new and desire tosecure by Letters Patent, is: i

1. That improvement in circulating air in a room which consists indischarging substantially horizontally across the room a central streamof air and at the same time propelled around said central stream aplurality of entwining, helically moving streams of air at such velocityand in suflicient amount to cause substantially all the air in the roomto revolve and move in harmony therewith.

2. That improvement in circulating air in a room which consists indischarging substantially horizontally across the room a central streamof helically moving air and at the same time propelling around thestream a plurality of entwining, helically moving streams of air at suchveloc-' ity and in sufficient amount to cause substantially all thesurrounding air in the room to revolve and move in'harmony therewith.

3. That improvement in circulating air in a room which consists indischarging horizontally across a room a central stream of air and atthe same time propelling around said central stream30 more than twoentwining, helically moving streams of air.

MAX WEBER.

